Jak naprzemiennie kolor tła w elementach HTML Div w CSS

/* to color odd children in parent-container with children of type div */
#parent-container > div:nth-child(odd) {
 background-color:red;
}

/* to color even children in parent-container with children of type div */
#parent-container > div:nth-child(even) {
 background-color:red;
}
Anxious Alligator